NCERT Solutions for Class 4th Maths Chapter 1 Nets, prisms and pyramids — Craft
Book page 3 Updated on2026-09-19
Q1.
Make a sphere-like shape with paper strips.
Paper strips of the same length joined at the top and at the bottom.
Answer
Cut equal paper strips and join them so they all bulge out together.
Cut 6 to 8 paper strips of the same length and
the same width.
Stack them one on top of the other.
Pin or staple all the strips together at the top end.
Pin or staple all of them together at the bottom end too.
Now spread the strips out all around, like the slices of an orange.
The shape you get is round in every direction — it looks like a sphere.
Why it happens: Every strip bends by the same amount, because
all the strips are of the same length. So the shape bulges equally on all sides, and a
shape that bulges equally on all sides is a sphere.
Check it yourself: If one strip is longer than the rest, it
sticks out and the shape is no longer round everywhere.
Q2.
Use the nets given at the end of the book to make the models shown below.
The six models given in the book: three prisms and three pyramids.A box folded open and flattened. The dotted lines are the folds.
Answer
Cut, fold and stick — the flat net turns into the solid.
Cut the net out along its outer line only.
Fold it along every dotted line. Press each fold hard.
Bring the faces up so they meet, and stick the flaps with glue or tape.
Do this once for each model: triangular prism, square prism, hexagonal prism,
triangular pyramid, square pyramid and pentagonal pyramid.
Why it happens: A net is the solid opened out flat. Every face
of the solid is already there in the net, so folding puts the faces back in place.
Tip: Count the faces on the net before you fold. A triangular
prism net has 3 rectangles and 2 triangles, so the solid must have 5 faces.
Q3.
What shape of face is common to all the prisms? _________________
The six models given in the book: three prisms and three pyramids.
Answer
The rectangle.
The triangular prism has rectangles on its sides.
The square prism has rectangles on its sides.
The hexagonal prism has rectangles on its sides.
Why it happens: A prism is made by taking one flat shape and
sliding it straight across. Every side of that shape sweeps out a flat rectangle.
Q4.
What other shapes do these prisms have? _________________
The six models given in the book: three prisms and three pyramids.
Answer
The two flat ends, and they are different in each prism.
Prism
Shape of the two end faces
Triangular prism
triangle
Square prism
square
Hexagonal prism
hexagon (6 sides)
Why it happens: A prism is named after the shape of its
two ends, so the ends tell you which prism it is.
Q5.
How many such faces each? _________________
The six models given in the book: three prisms and three pyramids.
Answer
2 in each prism — one at each end.
Triangular prism → 2 triangles
Square prism → 2 squares
Hexagonal prism → 2 hexagons
So each prism has 2 such faces.
Why it happens: The shape is slid straight across to make the
prism, so it appears once where it starts and once where it stops — two ends, and
the two ends are exactly the same.
Q6.
What shape of face is common to all the pyramids? _______________
The six models given in the book: three prisms and three pyramids.
Answer
The triangle.
The triangular pyramid has triangles on its slanting sides.
The square pyramid has triangles on its slanting sides.
The pentagonal pyramid has triangles on its slanting sides.
Why it happens: In a pyramid every side of the base is joined
to the same top point. A side joined to one point always makes a triangle.
Q7.
All the triangular faces meet at _________________ point.
The six models given in the book: three prisms and three pyramids.
Answer
All the triangular faces meet at one point.
That single point is the top corner of the pyramid.
Every triangle has one corner sitting exactly on that point.
Why it happens: A pyramid is made by joining each corner of the
base to the same top point, so all the triangles have to meet there.
Q8.
Identify any other shape in each of the pyramids _________________
The six models given in the book: three prisms and three pyramids.
Answer
The base — the flat face the pyramid stands on.
Pyramid
Shape of the base
Triangular pyramid
triangle
Square pyramid
square
Pentagonal pyramid
pentagon (5 sides)
Why it happens: A pyramid is named after the shape of its
base, so the base is the one face that is not a triangle (except in the triangular
pyramid, where even the base is a triangle).
Q9.
Is a cube also a prism?
The six models given in the book: three prisms and three pyramids.
Answer
Yes. A cube is a prism — it is the square prism.
Its two opposite faces are squares, and they are exactly
the same.
The four faces joining them are squares too, and a square is also a rectangle.
So a cube has matching ends joined by rectangles — that is what a prism is.
Why it happens: Slide a square straight across by the length of
its own side and you get a cube. That is exactly how a prism is made.
Q10.
What is the difference between a prism and a pyramid? Discuss.
The six models given in the book: three prisms and three pyramids.
Answer
Prism
Pyramid
Flat ends
2 matching ends
only 1 base
Side faces
rectangles
triangles
Do the side faces meet at a point?
no
yes, all at one top point
Looks like
a box or a tube with flat ends
a tent with a pointed top
Example
cube, triangular prism
square pyramid, triangular pyramid
Why it happens: A prism is made by sliding a shape straight
across, so both ends stay the same. A pyramid is made by pulling one shape up to a
single point, so it has one base and a sharp top.